Aneurysm treatment coils and associated systems and methods of use

ABSTRACT

Devices, systems, and methods for treating vascular defects are disclosed herein. One aspect of the present technology, for example, is directed toward an occlusive device having a distal end, a proximal end, and a longitudinal axis extending therebetween. The occlusive device may comprise an elongated member wound about the longitudinal axis to form a series of loops, wherein along at least some of the loops, the elongated member includes a first peak and a second peak axially offset from the first peak, the first peak being axially between the second peak and the proximal end. The first peak may be convex towards the distal end, and the second peak may be convex towards the proximal end.

TECHNICAL FIELD

The present technology relates to implantable devices for treatingvascular defects and associated systems and methods of use. Inparticular, the present technology is directed to occlusive coils fortreating cerebral aneurysms.

BACKGROUND

Aneurysms are blood-filled dilations of a blood vessel generally causedby disease or weakening of the blood vessel wall. The wall of theaneurysm may progressively thin, which increases the risk of rupturecausing hemorrhagic stroke or even sudden death. There are about 30,000to 40,000 cases of aneurysmal rupture per year in the United States,accounting for about 5% of all strokes. The prognosis after aneurysmalrupture is poor; the 30-day mortality rate is approximately 45% and apositive functional outcome is achieved in only 40-50% of survivors.

Traditional approaches to preventing aneurysmal rupture often includepacking the aneurysm with soft, helically-wound coils to reduce theinflow of blood to the aneurysm and prevent further enlargement andrupture. Conventional coils are created by transforming a metal wirefrom a primary structure to a secondary structure to a tertiarystructure. The primary structure is the “stock” wire, which isfabricated in linear form. The stock wire is wound around a mandrel(also known as the “primary wind” of the coil) to produce the secondarystructure of the coil. Finally, the secondary structure can be shapedinto any number of configurations (helical, complex, spherical, etc.)and heat set to form the tertiary structure of the coil. When the coilis released into an aneurysm cavity, it assumes its predeterminedtertiary structure.

One common tertiary structure used in conventional coils is a helicaltertiary structure (i.e., a coil of a coil), which is often referred tosimply as a “helical coil”. Conventional coils achieve the helicaltertiary structure by winding a secondary coil structure around acylindrical mandrel. Many conventional coils have helical tertiarystructures that can only deflect in one direction in response toresistive forces, which has several drawbacks. For example, when atraditional coil meets resistance while being pushed from amicrocatheter into the aneurysm cavity, the coil's inability to deflectin multiple directions causes energy to build along the coil. When thecoil finally breaks or deflects, the stored energy suddenly releases andoften times kicks the microcatheter tip out of position and/or pushesthe surrounding, already-implanted coils (and/or portions thereof) outof the aneurysm and into the parent vessel. Such herniated coils mayprolong the procedure, and often times require placement of anadditional device (such as a stent) and/or require anticoagulantmedication. In addition, because traditional helical coils can only bendin one direction, empty space in other directions will not be optimallypacked. Thus, the limited ability of traditional helical coils todeflect in multiple directions also leads to incomplete packing of theaneurysm. Clinically, if the aneurysm is not optimally packed, there isa strong likelihood of coil compaction and re-treatment may be needed.

Accordingly, there is a need for improved coils for treating vasculardefects.

SUMMARY

The subject technology is illustrated, for example, according to variousaspects described below, including with reference to FIGS. 1A-6. Variousexamples of aspects of the subject technology are described as numberedclauses (1, 2, 3, etc.) for convenience. These are provided as examplesand do not limit the subject technology.

Clause 1. An implantable device, comprising:

-   -   a coil having a proximal end, a distal end, and a longitudinal        axis extending therebetween, the coil formed of an elongated        member wound about the longitudinal axis of the coil in a series        of contiguous loops,    -   wherein each of the loops extend around the longitudinal axis        between a first end and a second end, the second end disposed at        generally the same angular position as the first end about to        the longitudinal axis of the coil, and    -   wherein the elongated member has a longitudinal axis extending        along its length, and wherein the elongated member undulates        along its longitudinal axis between the first and second ends of        at least some of the individual loops.

Clause 2. The implantable device of Clause 1, wherein the elongatedmember is wound about the longitudinal axis in a first direction, andwherein the elongated member extends distally along the first directionand also proximally along the first direction around the at least someof the individual loops.

Clause 3. The implantable device of Clause 1 or Clause 2, wherein theelongated member is wound about the longitudinal axis in a firstdirection, and wherein, along the at least some of the individual loops,the elongated member extends along the first direction proximally, thendistally, then proximally, and then distally.

Clause 4. The implantable device of any one of Clauses 1 to 3, whereinthe first end is at a different axial location than the second end.

Clause 5. The implantable device of any one of Clauses 1 to 4, whereinthe elongated member is a coiled wire.

Clause 6. The implantable device of any one of Clauses 1 to 5, whereinthe coil has a circular cross-sectional shape.

Clause 7. The implantable device of any one of Clauses 1 to 6, whereinthe coil forms a generally tubular structure.

Clause 8. The implantable device of any one of Clauses 1 to 7, whereinthe coil has bends along its longitudinal axis in a relaxed state.

Clause 9. The implantable device of any one of Clauses 1 to 8, whereinthe coil has a plurality of deflection regions along its longitudinalaxis, and wherein the coil is configured to deflect in differentdirections at different deflection regions.

Clause 10. An implantable device, comprising:

-   -   a coil formed of an elongated member wound about a longitudinal        axis of the coil in a series of contiguous loops, each of the        loops beginning and ending at generally the same angular        position about the longitudinal axis of the coil,    -   wherein, along at least some of the individual loops, the        elongated member has a plurality of alternating peaks and        valleys, the valleys being axially spaced apart from the peaks.

Clause 11. The implantable device of Clause 10, wherein the elongatedmember is a coiled wire.

Clause 12. The implantable device of Clause 10 or Clause 11, wherein thecoil has a circular cross-sectional shape.

Clause 13. The implantable device of any one of Clauses 10 to 12,wherein the coil forms a generally tubular structure.

Clause 14. The implantable device of any one of Clauses 10 to 13,wherein the coil is generally cylindrical.

Clause 15. The implantable device of any one of Clauses 10 to 14,wherein the coil has bends along its longitudinal axis in a relaxedstate.

Clause 16. The implantable device of any one of Clauses 10 to 15,wherein the coil has a plurality of deflection regions along itslongitudinal axis, and wherein the coil is configured to deflect indifferent directions at different deflection regions.

Clause 17. A method for forming an implantable device, the methodcomprising:

-   -   winding an elongated member about a shaft portion of a mandrel,        the shaft portion disposed along the mandrel between a proximal        forming member and a distal forming member;    -   axially constraining the wound member on the shaft between the        proximal and distal forming members such that a first        circumferential section of the wound member is urged distally        and a second circumferential section of the wound member is        urged proximally; and    -   heat-setting the elongated member while axially constrained on        the mandrel.

Clause 18. The method of Clause 17, wherein the shaft portion of themandrel is linear and has a generally constant diameter.

Clause 19. The method of Clause 17 or Clause 18, wherein the shaftportion of the mandrel has a generally constant diameter along itslength.

Clause 20. The method of any one of Clauses 17 to 19, wherein the woundmember is axially constrained on the shaft between an undulating,proximal face of the distal forming member and an undulating, distalface of the proximal forming member.

Clause 21. An implantable device, comprising:

-   -   a distal end, a proximal end, and a longitudinal axis extending        therebetween; and    -   an elongated member wound about the longitudinal axis to form a        series of loops, wherein along at least some of the loops, the        elongated member includes a first peak and a second peak axially        offset from the first peak, the first peak being axially between        the second peak and the proximal end, and wherein the first peak        is convex towards the distal end, and the second peak is convex        towards the proximal end.

Clause 22. The implantable device of Clause 21, wherein, for a given oneof the loops, the first peak and the second peak are free to moverelative to one another.

Clause 23. The implantable device of Clause 21 or Clause 22, wherein,for a given one of the loops, the first peak is about 360 degrees fromthe second peak about the longitudinal axis of the device.

Clause 24. The implantable device of any one of Clauses 21 to 23,wherein the elongated member is a coiled wire.

Clause 25. The implantable device of any one of Clauses 21 to 25,wherein the device has a circular cross-sectional shape in a relaxedstate.

Clause 26. The implantable device of any one of Clauses 21 to 26,wherein, for a given one of the loops, the first peak is not intertwinedwith the second peak.

Clause 27. The implantable device of any one of Clauses 21 to 26,wherein the device forms a generally tubular structure.

Clause 28. The implantable device of any one of Clauses 21 to 27,wherein the device has a predetermined shape in a relaxed, unconstrainedstate.

Clause 29. The implantable device of any one of Clauses 21 to 28,wherein the device has a plurality of deflection regions along itslongitudinal axis, and wherein the device is configured to deflect indifferent directions at different deflection regions.

Clause 30. An implantable device, comprising:

-   -   a distal end, a proximal end, and a longitudinal axis extending        therebetween; and    -   an elongated member wound about the longitudinal axis to form a        series of loops, the elongated member having a longitudinal axis        extending along its length, and wherein the elongated member        undulates along its longitudinal axis along each loop,    -   wherein each of the loops has a first end and a second, and        wherein, for at least some of the loops, the first end extends        towards the second end, and vice versa.

Clause 31. The implantable device of Clause 30, wherein immediatelyadjacent loops are spaced apart from one another.

Clause 32. The implantable device of Clause 30 or Clause 31, wherein theimplantable device is configured to be positioned within a cerebralaneurysm.

Clause 33. The implantable device of any one of Clauses 30 to 32,wherein the elongated member is a coiled wire.

Clause 34. The implantable device of any one of Clauses 30 to 33,wherein the elongated member forms a generally tubular structure.

Clause 35. The implantable device of any one of Clauses 30 to 34,wherein the device has a circular cross-sectional shape in a relaxedstate.

Clause 36. The implantable device of any one of Clauses 30 to 35,wherein the device has a predetermined shape in a relaxed, unconstrainedstate.

Clause 37. The implantable device of any one of Clauses 30 to 36,wherein the device has a plurality of deflection regions along itslongitudinal axis, and wherein the device is configured to deflect indifferent directions at different deflection regions.

Clause 38. A method for forming an implantable device, the methodcomprising:

-   -   winding an elongated member about a mandrel to form a series of        loops, wherein along at least some of the loops, the elongated        member includes a first peak and a second peak axially offset        from the first peak, the first peak being axially between the        second peak and the proximal end, and wherein the first peak is        convex towards the distal end, and the second peak is convex        towards the proximal end; and    -   heat-setting the elongated member while wound around the        mandrel.

Clause 39. The method of Clause 38, wherein the elongated member is acoil.

Clause 40. The method of Clause 38 or Clause 39, wherein the mandrel hasa substantially constant cross-sectional dimension along its length.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale. Instead, emphasis is placed on illustratingclearly the principles of the present disclosure.

FIG. 1A depicts an occlusive coil in accordance with the presenttechnology, shown in a relaxed state.

FIG. 1B is an enlarged side view of a portion of the coil shown in FIG.1A.

FIG. 1C is an enlarged end view of the coil shown in FIG. 1A.

FIGS. 2A-2C are different elongated members used for forming theocclusive coils of the present technology.

FIG. 3 shows an occlusive coil of the present technology being deployedwithin an aneurysm.

FIGS. 4A and 4B illustrate a method for manufacturing an occlusive coilin accordance with some embodiments of the present technology.

FIG. 5A depicts an occlusive coil in accordance with the presenttechnology, shown in a relaxed state.

FIG. 5B is an enlarged end view of the coil shown in FIG. 5A.

FIG. 6 shows a portion of the occlusive coil positioned on a mandrelduring manufacturing of the coil.

DETAILED DESCRIPTION

The present technology relates to occlusive coils and associated systemsand methods of use. Some embodiments of the present technology, forexample, are directed to occlusive coils for treating cerebralaneurysms. Specific details of several embodiments of the technology aredescribed below with reference to FIGS. 1A-6.

FIG. 1A shows an occlusive coil 100 (or “coil 100”) configured inaccordance with the present technology, shown in a relaxed state (i.e.,the theoretical three-dimensional configuration assumed by the coil 100as it would exist with no outside forces on it in its tertiaryconfiguration). The coil 100 has a proximal end 101 a, a distal end 101b, and a longitudinal axis A2 extending therebetween. As shown in FIG.1A, the coil 100 is formed of an elongated member 102 wound about thelongitudinal axis A2 and heat set in a novel helical tertiary structure.Unlike conventional helical coils that are generally straight in arelaxed state, the coil 100 has bends along its longitudinal axis A2between a plurality of deflection regions 104. As used herein withrespect to the coils of the present technology, a “deflection region” isan area that is more predisposed to bending than the portion of the coilthat is not part of a deflection region. One or more deflection regionsmay be predisposed to bending in one or more first directions and one ormore different deflection regions may be predisposed to bending in oneor more second directions. The one or more first directions may be thesame or different from the one or more second directions. The deflectionregions 104 allow the coil 100 to bend in multiple directions, whichprovides several advantages over conventional helical coils that arelimited to a single bend direction. For example, the coil's 100 abilityto bend in multiple directions allows the coil 100 to bend sooner inresponse to resistive forces during deployment. As such, the coil 100builds up less energy during deployment than a conventional coil (if anyat all), thus eliminating or greatly reducing the severity of theeffects of a sudden “break” or deflection. As a result, the coil 100 ofthe present technology reduces the potential for catheter kick-out andcoil herniation, thus reducing procedure complications. Moreover, thecoil's ability to deflect in multiple directions allows it to seek andpack empty space within a coil-packed aneurysm, thereby increasing theaneurysm packing volume and reducing the chance of retreatment due tocoil compaction.

FIG. 1B is an enlarged side view of a portion of the coil 100, and FIG.1C is an end view of the coil 100. Referring to FIGS. 1A-1C together,the elongated member 102 may be wound about the longitudinal axis A2 ofthe coil 100 in a series of contiguous loops or windings, four of whichare shown in FIG. 1B and labeled 108 a-d. Each of the loops extendaround the longitudinal axis A2 between a first end and a second end(labeled 114, 116 for loop 108 a; second end 116 not visible in FIG.1B), where the second end is disposed approximately 360 degrees from thefirst end about the longitudinal axis A2 of the coil 100. That is, thefirst and second ends are disposed at generally a same angular positionrelative to the longitudinal axis A2 of coil 100. As shown in FIG. 1C,in some embodiments the coil 100 has a circular cross-sectional shape.In other embodiments, the coil 100 may have other suitablecross-sectional shapes (e.g., oval, square, triangular, polygonal,etc.). The cross-sectional shape of the coil 100 may be generally thesame or vary along the length of the coil 100 and/or from loop to loop.Likewise, the diameter of the coil 100 may be generally constant or varyalong the length of the coil 100 and/or from loop to loop (usuallybetween about 2 mm and about 20 mm). In some embodiments, the coil 100has a generally cylindrical shape.

In some embodiments, such as that shown in FIGS. 1A-1C, the elongatedmember 102 is also a coiled structure. For example, FIG. 2A shows theelongated member 102 in its secondary form, prior to being wound andheat set to form the helical tertiary structure of FIGS. 1A-1C. In suchembodiments where the elongated member 102 is a coil, the elongatedmember 102 may be formed of a wire 106 wound about a longitudinal axisA1 to form a generally tubular structure, as shown in FIG. 2A. Theelongated member 102 may have a pitch that is constant or varies overits length. Likewise, the coil 100 may have a pitch that is constant orvaries over its length. In some embodiments, the elongated member 102does not comprise a coil and instead comprises an uncoiled, solid wire(FIG. 2B) or an uncoiled tube (FIG. 2C). The elongated member 102 may bemade of any material suitable for forming an occlusive device, such asnitinol, platinum, rhodium, palladium, tungsten, gold, silver,cobalt-chromium, and/or various alloys of these materials.

As best shown in FIGS. 1B and 1C, the elongated member 102 may undulatealong its longitudinal axis A1 as it winds around the longitudinal axisA2 of the coil 100, forming a plurality of alternating peaks (closer tothe distal end 101 a of the coil 100) and valleys (closer to theproximal end 101 a of the coil 100). The valleys are at a differentlocation along the longitudinal axis A1 than the peaks (i.e., areaxially spaced apart from the peaks). For example, for loop 108 a, inthe direction of the wind W (clockwise or counterclockwise), theelongated member 102 extends proximally from the first end 114 to afirst valley 120 a, then distally to a first peak 122 a, then proximallyto a second valley 120 b, then distally to a second peak 122 b, thenproximally to a third valley 120 c, then distally to a third peak 122 c,then proximally to a fourth valley 120 d (not visible in FIG. 1B), thendistally to a fourth peak 122 d (not visible in FIG. 1B), whichcoincides with the second end 116 of loop 108 a. Stated otherwise, whentraveling in a direction of the wind W around a given loop, the loopdoes not consistently progress distally or proximally, but ratherundulates so that along certain portions of its length, the loop becomesprogressively more proximal, and along other portions of its length theloop becomes progressively more distal. Although the first and secondends 114, 116 may be generally aligned circumferentially, the first andsecond ends 114, 116 are disposed at different axial locations.

Although FIGS. 1B and 1C show a coil embodiment having four peaks andfour valleys per loop, in some embodiments the coil 100 has more orfewer peaks and/or more or fewer valleys in a given loop. For example,in some embodiments the coil has one, two, three, four, five, six,seven, eight, etc. peaks per loop and one, two, three, four, five, six,seven, eight, etc. valleys per loop. The loops may have the same or adifferent number of peaks, and the loops may have the same or adifferent number of valleys. In addition, the amplitude of the peaks maybe the same or different along a given loop and/or amongst the loops,and the amplitude of the valleys may be the same or different along agiven loop and/or amongst the loops. Moreover, the peaks and valleys canhave the same or different amplitudes.

In some embodiments, all of the loops have an undulating shape, and insome embodiments at least some of the loops have a non-undulating shape(i.e., a straight helical turn). Moreover, in some embodimentssuccessive loops are nested, i.e., immediately adjacent to and/or incontact with one another along most of their circumferential lengths (asshown in FIG. 1B). In other embodiments one or more successive loops arespaced apart along all or a portion of their respective circumferentiallengths. In particular embodiments, the coil 100 includes both nestedand spaced apart loops. In addition, the number of loops may varydepending on the desired length of the coil 100. The length of the coil100, for example, may be from about 2 cm to about 80 cm, depending onthe application for which it will be used.

FIG. 3 shows the coil 100 in a deployed state positioned within ananeurysm A. As used herein, “deployed configuration” or “deployed state”refers to the shape of the coil 100 after it has been deployed from adelivery catheter (e.g., a microcatheter). The deployed configuration ofa particular device may differ, depending on whether the device isdeployed into the open, or whether it is deployed into a body cavitywhich may influence its three-dimensional structure. As shown in FIG. 3,the coil 100 may be intravascularly delivered to the aneurysm cavity C(such as a cerebral aneurysm) via a delivery catheter (e.g., amicrocatheter). With the distal tip of the catheter 150 positionedwithin the aneurysm A (or at least at the neck of the aneurysm A), thecoil 100 is pushed distally from the catheter tip into the cavity C. Asadditional coils (or additional length of a given coil) are deliveredinto the cavity C and the packed volume increases, subsequent coils 100will experience increased resistance when exiting the catheter. Unliketraditional helical coils that cannot bend in multiple directions inresponse to this resistance, the coil 100 can bend/deflect in multipledirections. Thus, as previously mentioned, the coil 100 of the presenttechnology reduces the potential for catheter kick-out and coilherniation, thus reducing procedure complications. Moreover, the abilityto deflect in multiple directions allows the coil 100 to seek and packempty space within a coil-packed aneurysm, thereby increasing theaneurysm packing volume and reducing the chance of retreatment due tocoil compaction.

FIGS. 4A and 4B illustrate a system 200 and method for manufacturingocclusive coils in accordance with some embodiments of the presenttechnology, including coil 100. As shown in FIGS. 4A and 4B, the system200 may include a mandrel 201 having a shaft portion 202 and a proximalforming member 204 a and a distal forming member 204 b on either side ofthe shaft portion 202. In some embodiments, including the embodimentshown in FIGS. 4A and 4B, the shaft portion 202 is generally cylindrical(i.e., has a generally circular cross-section and a constant diameteralong its length). In other embodiments, the shaft portion 202 can haveother cross-sectional shapes and/or have a varying cross-sectionaldimension along its length.

The proximal forming member 204 a may have an undulating, distal face206 a and the distal forming member 204 b may have an undulating,proximal face 206 b that faces the distal face 206 a of the proximalforming member 204 a. As shown in FIGS. 4A and 4B, the distal andproximal faces 206 a, 206 b may have a complementary topography suchthat the peaks of the proximal face 206 b are circumferentially alignedwith the valleys of the distal face 206, and vice versa. The undulationsof the distal and proximal faces, 206 a, 206 b may be curved (as inFIGS. 4A and 4B), or all or a portion of the undulations may be linear.

In some embodiments of making the coil 100, the elongated member 102 maybe wound around the shaft portion 202 of the mandrel 201 with a proximalend of the wound member spaced apart from the proximal face 206 b andthe distal end of the wound member spaced apart from the distal face 206a. The proximal and distal forming members 204 a, 204 b may then bemoved towards one another to contact and exert axially compressiveforces on the proximal and distal ends of the wound member, therebyforcing the wound member to take the undulating shape of the faces 206a, 206 b along its entire length. For example, the proximal and distalforming members 204 a, 204 b may urge a first circumferential section ofthe wound member distally (thereby forming the peaks) and a secondcircumferential section of the wound member proximally (thereby formingthe valleys). While in this axially constrained configuration, theelongated member 102 is then heat-set to form the coil 100.

FIG. 5A shows a portion of the length of an occlusive coil 300 (or “coil300”) configured in accordance with the present technology, shown in arelaxed, unconstrained state, and FIG. 5B is an end view of the coil300. Referring to FIGS. 5A and 5B together, the coil 300 has a proximalend 301 a, a distal end 301 b, and a longitudinal axis A2 extendingtherebetween. As shown in FIG. 5A, the coil 300 is formed of anelongated member 302 wound about the longitudinal axis A2 and heat setin a novel helical tertiary structure. Similar to coil 100, the coil 300is configured to bend in multiple directions, which provides severaladvantages over conventional, unidirectional-bending helical coils, suchas a reduced potential for catheter kick-out and coil herniation, andincreased aneurysm packing volume potential.

In some embodiments, including that shown in FIGS. 5A and 5B, theelongated member 302 is also a coiled structure. For example, similar tothe elongated member 102 shown in FIG. 2A, the elongated member 302 mayhave a secondary form prior to being wound and heat set to form thehelical tertiary structure of FIGS. 5A and 5B. In such embodiments wherethe elongated member 302 is a coil, the elongated member 302 may beformed of a wire (such as wire 106) wound about a longitudinal axis A1to form a generally tubular structure, as shown in FIG. 2A. Theelongated member 302 may have a pitch that is constant or varies overits length. Likewise, the coil 300 may have a pitch that is constant orvaries over its length. In some embodiments, the elongated member 302does not comprise a coil and instead comprises an uncoiled, solid wire(FIG. 2B) or an uncoiled tube (FIG. 2C). The elongated member 302 may bemade of any material suitable for forming an occlusive device, such asnitinol, platinum, rhodium, palladium, tungsten, gold, silver,cobalt-chromium, and/or various alloys of these materials.

As best shown in FIG. 5B, the coil 300 may have a circularcross-sectional shape. In some embodiments, the coil 300 may have othersuitable cross-sectional shapes (e.g., oval, square, triangular,polygonal, etc.). The cross-sectional shape of the coil 300 may begenerally the same or vary along the length of the coil 300 and/or fromloop to loop. Likewise, the diameter of the coil 300 may be generallyconstant or vary along the length of the coil 300 and/or from loop toloop (usually between about 2 mm and about 20 mm).

The elongated member 302 may be wound about the longitudinal axis A2 ofthe coil 300 in a series of contiguous loops or windings. Each of theloops extend around the longitudinal axis A2 between a first end and asecond end that is disposed about 360 degrees from the first end aboutthe longitudinal axis A2 of the coil 300. The elongated member 302 mayundulate along its longitudinal axis A1 as it winds around thelongitudinal axis A2 of the coil 100, forming a plurality of alternatingpeaks. Along a given loop, the elongated member 302 may start at a firstpeak 304 a and end at a second peak 304 b that is axially offset fromthe first peak 304 a.

As shown in FIG. 5A, the first peak 304 a may form a curved structure orlength of the elongated member 302 that is convex towards the distal end301 b of the coil 300. In those embodiments where the elongated member302 is a coil (such as the embodiment shown in FIG. 5A), the curvedstructure of the first peak 304 a may comprise multiple turns of thewire that forms the coil (such as wire 106 in FIG. 2A). For example, thecurved structure may extend between end turn 305 a and end turn 305 band include the one or more intermediate turns between end turns 305 aand 305 b. In some embodiments, at least one point on the wire along theone or more intermediate turns is more distal than any point on eitherof end turns 305 a or 305 b. In some embodiments, the entire length ofthe wire along one or more intermediate turns is more distal than anypoint on either of end turns 305 a or 305 b.

The second peak 304 b may form a curved structure or length that isconvex towards the proximal end 301 a of the coil 300. The curvedstructure of the second peak 304 b may comprise multiple turns of thewire that forms the coil (such as wire 106 in FIG. 2A). For example, thecurved structure may extend between end turn 305 c and end turn 305 dand include the one or more intermediate turns between end turns 305 cand 305 d. In some embodiments, at least one point on the wire along theone or more intermediate turns is more proximal than any point on eitherof end turns 305 c or 305 d. In some embodiments, the entire length ofthe wire along one or more intermediate turns is more proximal than anypoint on either of end turns 305 c or 305 d.

Referring still to FIG. 5A, the first and second peaks 304 a, 304 b mayextend towards one another. The axial distance between the second peak304 b and the distal end 301 b of the coil 300 may be less than thedistance between the first peak 304 a and the distal end 301 b.Likewise, the distance between the first peak 304 a and the proximal end301 a may be less than the distance between the second peak 304 b andthe proximal end 301 a. As shown in FIG. 5A, the adjacent loops of thecoil 300 may be spaced apart from one another along the longitudinalaxis A2 of the coil.

The coil 300 may have any number of loops (e.g., two, three, four, five,six, etc.). The coil 300 may have one, two, three, four, five, six,seven, eight, etc. peaks per loop. The loops may have the same or adifferent number of peaks, and the loops may have the same or adifferent number of valleys. In addition, the amplitude of the peaks maybe the same or different along a given loop and/or amongst the loops.Moreover, the peaks can have the same or different amplitudes. In someembodiments, all of the loops have an undulating shape, and in someembodiments at least some of the loops have a non-undulating shape(i.e., a straight helical turn).

In use, the coil 300 may be delivered to an aneurysm (such as a cerebralaneurysm) as described above for coil 100 with reference to FIG. 3.

FIG. 6 shows a portion of the elongated member 302 positioned on amandrel 402 during manufacturing of the coil 300. (For ease of viewingthe tertiary structure of the coil 300, the elongated member 302 isshown as a non-coiled wire in FIG. 6.) As shown in FIG. 6, the mandrel402 may have a series of circumferentially- and axially-spaced posts 404(only one labeled in FIG. 6 for ease of illustration), and the elongatedmember 302 may be wound about the mandrel 402 and around the posts 404.In some embodiments, including the embodiment shown in FIG. 6, the shaft402 is generally cylindrical (i.e., has a generally circularcross-section and a constant diameter along its length). In otherembodiments, the shaft 402 can have other cross-sectional shapes and/orhave a varying cross-sectional dimension along its length. While in thiswound configuration, the elongated member 302 is then heat-set to formthe coil 300.

While on the mandrel, the coil 300 may include a plurality of overlapregions 308 spaced apart about its circumference (only one overlapregion is labeled in FIG. 6). Within the overlap regions 308, the firstpeak 304 a may be axially aligned with or extend beyond the second peak306 b. The first and second peaks 304 a, 304 b are not intertwined suchthat the first peak 304 a is free to move relative to the second peak306 b, and vice versa. As such, after being heat set and removed fromthe mandrel, the coil 300 assumes a relaxed state (as shown in FIG. 5A)in which at least some of the adjacent loops of the coil 300 separatefrom one another, and the previously-overlapping first and second peaks304 a, 304 b are spaced apart. As such, the portions of the first andsecond peaks 304 a, 304 b that extended beyond one another when on themandrel now form the convex structures that point towards one another asdescribed in FIG. 5A. In some embodiments, no portion of the elongatedmember 302 is intertwined with no other portion of the elongated member302. In some embodiments, some portions of the elongated member 302 areintertwined.

CONCLUSION

Although many of the embodiments are described above with respect tosystems, devices, and methods for treating cerebral aneurysms, thetechnology is applicable to other applications and/or other approaches,such as the treatment of other aneurysms or vascular defects. Moreover,other embodiments in addition to those described herein are within thescope of the technology. Additionally, several other embodiments of thetechnology can have different configurations, components, or proceduresthan those described herein. A person of ordinary skill in the art,therefore, will accordingly understand that the technology can haveother embodiments with additional elements, or the technology can haveother embodiments without several of the features shown and describedabove with reference to FIGS. 1A-6.

The above detailed descriptions of embodiments of the technology are notintended to be exhaustive or to limit the technology to the precise formdisclosed above. Where the context permits, singular or plural terms mayalso include the plural or singular term, respectively. Althoughspecific embodiments of, and examples for, the technology are describedabove for illustrative purposes, various equivalent modifications arepossible within the scope of the technology, as those skilled in therelevant art will recognize. For example, while steps are presented in agiven order, alternative embodiments may perform steps in a differentorder. The various embodiments described herein may also be combined toprovide further embodiments.

Moreover, unless the word “or” is expressly limited to mean only asingle item exclusive from the other items in reference to a list of twoor more items, then the use of “or” in such a list is to be interpretedas including (a) any single item in the list, (b) all of the items inthe list, or (c) any combination of the items in the list. Additionally,the term “comprising” is used throughout to mean including at least therecited feature(s) such that any greater number of the same featureand/or additional types of other features are not precluded. It willalso be appreciated that specific embodiments have been described hereinfor purposes of illustration, but that various modifications may be madewithout deviating from the technology. Further, while advantagesassociated with certain embodiments of the technology have beendescribed in the context of those embodiments, other embodiments mayalso exhibit such advantages, and not all embodiments need necessarilyexhibit such advantages to fall within the scope of the technology.Accordingly, the disclosure and associated technology can encompassother embodiments not expressly shown or described herein.

I/We claim:
 1. An implantable device, comprising: a distal end, aproximal end, and a longitudinal axis extending therebetween; and anelongated member wound about the longitudinal axis to form a series ofloops, wherein along at least some of the loops, the elongated memberincludes a first peak and a second peak axially offset from the firstpeak, the first peak being axially between the second peak and theproximal end, and wherein the first peak is convex towards the distalend, and the second peak is convex towards the proximal end.
 2. Theimplantable device of claim 1, wherein, for a given one of the loops,the first peak and the second peak are free to move relative to oneanother.
 3. The implantable device of claim 1, wherein, for a given oneof the loops, the first peak is about 360 degrees from the second peakabout the longitudinal axis of the device.
 4. The implantable device ofclaim 1, wherein the elongated member is a coiled wire.
 5. Theimplantable device of claim 1, wherein the device has a circularcross-sectional shape in a relaxed state.
 6. The implantable device ofclaim 1, wherein, for a given one of the loops, the first peak is notintertwined with the second peak.
 7. The implantable device of claim 1,wherein the device forms a generally tubular structure.
 8. Theimplantable device of claim 1, wherein the device has a predeterminedshape in a relaxed, unconstrained state.
 9. The implantable device ofclaim 1, wherein the device has a plurality of deflection regions alongits longitudinal axis, and wherein the device is configured to deflectin different directions at different deflection regions.
 10. Animplantable device, comprising: a distal end, a proximal end, and alongitudinal axis extending therebetween; and an elongated member woundabout the first longitudinal axis to form a series of loops, wherein theelongated member has a longitudinal axis extending along its length, andwherein the elongated member undulates along its longitudinal axis alongeach loop, wherein each of the loops has a first end and a second, andwherein, for at least some of the loops, the first end extends towardsthe second end, and vice versa.
 11. The implantable device of claim 10,wherein immediately adjacent loops are spaced apart from one another.12. The implantable device of claim 10, wherein the implantable deviceis configured to be positioned within a cerebral aneurysm.
 13. Theimplantable device of claim 10, wherein the elongated member is a coiledwire.
 14. The implantable device of claim 10, wherein the elongatedmember forms a generally tubular structure.
 15. The implantable deviceof claim 10, wherein the device has a circular cross-sectional shape ina relaxed state.
 16. The implantable device of claim 10, wherein
 17. Theimplantable device of claim 10, wherein the device has a plurality ofdeflection regions along its longitudinal axis, and wherein the deviceis configured to deflect in different directions at different deflectionregions.
 18. A method for forming an implantable device, the methodcomprising: winding an elongated member about a mandrel to form a seriesof loops, wherein along at least some of the loops, the elongated memberincludes a first peak and a second peak axially offset from the firstpeak, the first peak being axially between the second peak and theproximal end, and wherein the first peak is convex towards the distalend, and the second peak is convex towards the proximal end; andheat-setting the elongated member while wound around the mandrel. 19.The method of claim 18, wherein the elongated member is a coil.
 20. Themethod of claim 18, wherein the mandrel has a substantially constantcross-sectional dimension along its length.